Shrink-package construction

ABSTRACT

The invention contemplates use of heat-shrinkable plastic film for the packaging of clusters of containers, such as cylindrical beverage cans of a given size, and clustered in a pattern, as in the familiar &#39;&#39;&#39;&#39;2 X 3 six-pack,&#39;&#39;&#39;&#39; for which at least one dimension comprises a plural odd-integer number of containers. As described herein, the film is s circumferential wrap from a sheet, wherein ends of the sheet establish a region of overlap at the bottom of the cluster, the direction of wrap being such as to establish upstanding side panels along clusters sides characterized by the plural odd-integer number. The top panel is characterized by two like parallel slits which are spaced substantially to the extent of the container diameter, the slits extending in the wrap direction and symmetrically straddling the center of the cluster. By performing the slitting operation after the shrinking operation, there is negligible exposure of the containers to dust or contamination via the slits, yet the slits define a simple and highly effective &#39;&#39;&#39;&#39;handle&#39;&#39;&#39;&#39; for central and correct application of lifting effort, in unit-handling portability of the package.

United States Patent [191 Morgese et al.

[451 Sept. 10,1974

[ SHRINK-PACKAGE CONSTRUCTION [75] Inventors: Nicholas V. Morgese, Garnerville,

N.Y.; Robert H. Ganz, Saddle River, NJ.

[731' Assignee: Ganz Brothers, Inc., Bergenfield,

22 Filed: Aug. 10, 1972 [21] App]. No.: 279,718

[52] US. Cl. 206/161, 206/432 [51] Int. Cl B65d 71/00 [58] Field of Search 206/655, 65 C [56] References Cited UNITED STATES PATENTS 2,872,036 2/1959 Forrer 206/65 C 2,946,621 7/1960 Williamson 206/65 C X 3,215,266 11/1965 Dreyfus 206/65 S 3,302,784 2/1967 Copping..... 3,400,810 9/1968 Makowski 206/65 S 3,660,961 5/1972 Ganz 53/26 Primary ExaminerLeonard Summer Attorney, Agent, or Firm-Sandoe, Hopgood and Calimafde ABSTRACT The invention contemplates use of heat-shrinkable plastic film for the packaging of clusters of containers, such as cylindrical beverage cans of a given size, and clustered in a pattern, as in the familiar 2X3 sixpack, for which at least one dimension comprises a plural odd-integer number of containers. As described herein, the film is s circumferential wrap from a sheet, wherein ends of the sheet establish a region of overlap at the bottom of the cluster, the direction of wrap being such as to establish upstanding side panels along clusters sides characterized by the plural odd-integer number. The top panel is characterized by two like parallel slits which are spaced substantially to the extent of the container diameter, the slits extending in the wrap direction and symmetrically straddling the center of the cluster.

By performing the slitting operation after the shrinking operation, there is negligible exposure of the containers to dust or contamination via the slits, yet the slits define a simple and highly effective handle for central and correct application of lifting effort, in unit-handling portability of the package.

3 Claims, 4 Drawing Figures PAIENTEBsm 0 an a 0575? men PPM/6- SHRINK-PACKAGE CONSTRUCTION The invention relates to shrink-packaging of clusters of containers, such as cylindrical beverage cans of a given size. Specifically, the invention is concerned with improvements over the disclosure of Ganz, US. Pat. No. 3,660,961, and it is also applicable to wrapping or enveloping techniques beyond those described in said application.

The development of shrink-packaging, especially the shrink-packaging of clusters of cylindrical beverage containers, for example, the popular 2X3 six-pack of 12-02. cans, is extremely competitive, the primary aim being to produce at least cost, not only a sufficiently attractive display of the containers in a package that will withstand abusive handling, but also a package which will be readily portable with simple access for container removal from the cluster. Inevitably, cost of materials is the biggest factor, but portability suffers when the shrink-film material is of too-thin gauge.

It is, accordingly, an object of the invention to provide an improved cluster package of the character indicated, and a method and apparatus for making the same.

Another object is to achieve superior portability for a shrink-wrap cluster package, using shrink-film of a gauge previously considered unacceptably thin.

A further object is to achieve the above objects without degrading overall ruggedness of the package and providing even easier access for container removal from the cluster.

It is also an object to achieve the above objects using existing wrapping machinery and methods, with a minimum of modification and without affecting the efficiency or speed of wrapping.

A still further object is to meet the above objects with a structure which is immediately portable, without breaking any part of the enveloping material.

A general overall object is to achieve major economies in unit-package cost while meeting the above objects, and without resort to inserted paperboard or the like reinforcements. I

Other objects and various further features of novelty and invention will be pointed out or will occur to those skilled in the art from a reading of the following specification, in conjunction with the accompanying drawings. In said drawings, which show, for illustrative purposes only, preferred forms of the invention:

FIG. 1 is a simplified view in perspective of a shrinkwrapping production line to which our invention has been applied,

FIG. 2 is an enlarged fragmentary view in elevation of slitting means used in FIG. 1, the elevation being a front look at oncoming articles on the production line;

FIG. 3 is an enlarged perspective view of a 2X3 six pack, being a product of the machine of FIG. 1; and

FIG. 4 is'a simplified side elevation of the article of FIG. 3, on a reduced scale, to illustrate portable use.

The invention is shown in connection with a production-line machine (FIG. 1) for shrink-packaging a 2X3 six-pack (FIG. 2) of like cylindrical containers, such as 12-02. beverage cans. The machine operates continuously, using generally horizontal clusterconveyor means running from left to right (in the sense of FIG. 1 as suggested by arrow designations, and also using a continuous elongated sheet or film of shrinkwrap material such as polyethylene having bi-axial shrink properties, the primary shrink axis, i.e., the axis along which the greatest potential for shrinkage in the presence of heat, being the direction of supply of the shrink material.

The machine of FIG. 1 may be essentially as described in detail in said Ganz patent. It suffices for present purposes to explain that cluster-forming mechanism, as described in said application, delivers 2X3 clusters to the conveyor, in regular short spacings between clusters. For purposes of simplified identification, clusters are suggested in FIG. 1 by an alphabetic succession, A, B, C M, N, working back from the almost completely produced cluster package A, which is shown completed and in greater detail in FIG. 3. The incoming unwrapped cluster N provides a convenient place to identify a typical cluster as comprising six like cylindrical containers 10-11-12-13-14-15, in closely nested array, with the longitudinal or three-container axis of the cluster oriented transverse to the longitudinal axis of conveyor movement. Shrink material 16, of width greater than the three-container dimensional extent of each cluster, and continuously supplied from a reel 17, is fed over suitable guide, tension, and the like roll systems, suggested at 18, to cluster-wrapping mechanism 19; the latter mechanism is only schematically indicated because it is fully described in said patent, and continuous drive thereof, in synchronism with conveyor movement is suggested by an input shaft 20, operative upon endless sprocket or the like means 21.

The wrapped cluster at C. illustrates the product of wrapping by the mechanism 19, and just prior to entry into a shrink atmosphere, provided by an oven or heat tunnel 22. At cluster C, the six containers are seen to be symmetrically and centrally grouped between lateral margins of a cut-off length 16' of the sheet material, in a tight circumferential wrap defining upstanding side panels 23-24, a top panel 25, and a bottom panel; the bottom panel consists of the spaced cut-off longitudinal ends 26-27 of the length 16, the ends 26-27 being overlapped in a central region of the bottom panel.

Cluster B is shown being exposed to a shrinking and bonding atmosphere, where the front and back flaps or ends 26-27 are bonded concurrently with the shrink action, in the course of accelerated conveyor transport through the heat tunnel 22. Preferably, clustertransport through the heat tunnel provides a localized heat-shielding function (as by spaced longitudinally aligned container-support systems 28-29-30), so that in the region of overlap of flaps 26-27 the heat-bonded development is not continuous but, rather, is at spaced locales along the overlap; these locales are identified W-X-Y-Z in FIGS. 3 and 4. The support systems28-2- 9-30 are each seen as an endless succession of linked tread-type shield elements, driven in unison by a synchronizing speed-up connection 31 to the inp ut shaft 20; only a small fraction of these elements is in tunnel 22 at any given instant, and so they tend to be cooled in their greater exposure to and movement through ambient air, thus affording the desired local heat-shield function. As explained in copending Ganz application, Ser. No. 29,127, filed Apr. 16, 1970, the bonded locales occur at both ends of the overlap (zones W and Z) and in regions between longitudinal alignment of container centers, i.e., zone X (between the center alignment for the container pair 10-13 and the center alignment for the container pair 11-14) and zone Y (between the center alignment for the container pair 11-14 and the center alignment for the container pair 12-15). The shrink action collapses the overhung ends of wrapped material, to define a continuous band over both ends of the wrapped cluster, leaving end openings for direct access to a container.

The shrink-processed article cools quickly to room temperature upon issue from the heat tunnel, with a tight contour-conforming set of the shrink material, as shown at cluster A and in FIG. 3. It is at this phase, and preferably before awaiting total return to room temperature, that we perform the slitting operation of the invention, using means shown in a fragmentary and simplified manner at 32 in FIGS. 1 and 2.

Briefly, the slitting means 32 may comprise two like knife blades 33-34 fixedly suspended from a saddle 35 which spans the conveyor and clears the path of cluster transport, between spaced uprights 36-37, which may be parts of the machine frame. The blades 33-34 are held by clamps 38 at a backward or trailing rake angle, with their cutting edges facing the oncoming shrunk packages", the blades 33-34 are also spaced to accord with the container diameter, as will be clear in FIG. 2. FIG. 2 also illustrates that for the case of cans -1- 1-12 of current style, with longitudinal ends necked-in so that chimed top and bottom panel connections may be at less than full container diameter, the knife blades 33-34 are positionable so as to clear adjacent passing chimes at the top panel, while also clearing the container bodies at the region of necking-in. The product issuing from the slitting operation is immediately ready for larger carton packaging in desired multiples, to suit various shipping requirements.

Referring particularly to FIG. 3, the completed article is seen to use the cut-off sheet 17' to tightly and securely retain the six containers (10 to in a nested 2X3 array, wherein the cut longitudinal ends (26-27) are locally bonded at the spaced regions W-X- -Y-Z. Slitting occurred on alignments of the vertical planes in which outer container pairs 10-13 (and 12-15) are adjacent the central pair 11-14, and since slitting occurred after shrinking, the cut slits 39-40 appear as single lines; in other words, the slits 39-40 do not so widen as to noticeably expose containers to dust or other contamination within the body of the package. The central bonded regions X-Y intersect the same vertical planes, leaving unbonded regions therebetween, on essentially the longitudinal alignments of container pairs (10-13, 11-14, and 12-15). The outer bonded regions W-Z extend continuously to the bottom of the shrunken end openings, as at 41.

FIG. 4 illustrates that the completed package can be presented (as described) to the customer, as at a selfservice market shelf. No puncturing of sheet material is necessary to derive a secure lifting removal of the package. The thumb and middle finger need only be inserted, with negligible resistance, at the central voids 42-43 of the cluster; upon thereafter bringing these fingers together while lifting, a central strap portion stretches slightly under the pendulous-weight of the package, allowing all remaining fingers to be inserted under the handle 25, and in place of the thumb, if desired.

FIG. 4 serves additionally to illustrate our belief as to why the described construction offers advantages over constructions previously known to me. Since the slits 39-40 extend the full width (longitudinal extent, in terms of conveyor movement) of the top panel 25, the primary take-up of lifting-load stress at the handle" 25 is longitudinal, i.e., in the wrap direction, and is distributed over the expansive area of the side panels 23-24. Further, since the central vertical plane of symmetry of the lift force is that of the centers of the central container pair 11-14 (i.e., between bonded regions X-Y), there will be a slight stretch or yield at this central plane, causing the spaced bonded regions X-Y to share the load, along somewhat diagonally spreading alignments, suggested at 44-45. This spread-out sharing of the load also enables the outer bonded regions W-Z to contribute their share of load take-up generally along alignments 46-47, and it is found that one can avoid such localized stress concentrations as might otherwise tear the slit panel material, in the presence of handle-lift forces. The ability to distribute lifting-force reaction vectors will be seen as inviting the economy of thinnergauge materials without impairing the integrity of cluster retention; specifically, a 2-mil thick polyethylene shrink-wrapped package with slit formations 39-40 has been found to provide a handle 25 lifting strength more than double the filled weight of a 2X3 six-pack of 12-02, containers, and such strength exceeded that available for a 3-mil polyethylene package having the fingerhole-pierced top-panel construction described in said Ganz patent.

Not only does the described construction enable efficient spreading of vector components of load take-up, but it also presents better and more facile access to the package, as when it is desired to remove one or two containers without necessarily destroying the rest of the package. One need only introduce one or several fingers trhough one of the slits 39-40, and then tear outwardly, i.e., toward the nearest adjacent end opening 41. This will be a pull in the direction of least shrinkability of the material and, therefore, in the direction of most readiness for tearing and container access. Any tear involved in such removal of a container does not affect security of the remainder of the package; in fact, upon removal of a container, the center of gravity of the remainder is shifted in the direction favoring fidelity of support through the untorn remainder and thus favoring retention of remaining containers, even when lifted by the same handle 25'.

While the invention has been described in detail for the preferred form shown, it will be understood that modifications may be made without departing from the scope of the invention.

What is claimed is:

1. A 2X3" package of six like upstanding cylindrical containers in side-by-side adjacency, and a circumferential wrap of shrunk plastic sheet material enveloping said cluster over the top ends of said containers and continuously over adjacent upstanding three-container sides and the bottom of said cluster, thereby defining upper and side and bottom panels of said wrap, said upper panel providing the only cover of said top ends and having spaced slits along two parallel horizontal alignments which are substantially in registry with the upper-panel intercept of the vertical planes in which the center two containers are adjacent to their respective next-adjacent outer containers of the array, said bottom panel including overlapped edges of wrapped sheet material, said edges being bonded to each other at spaced regions which are also intercepted by said material is of the bi-axially oriented variety, the direction of primary shrink potential being the direction of wrap.

3. The package of claim 1, wherein said sheet material is biaxially oriented polyethylene, the direction of primary shrink potential being the direction of wrap. 

1. A ''''2 X 3'''' package of six like upstanding cylindrical containers in side-by-side adjacency, and a circumferential wrap of shrunk plastic sheet material enveloping said cluster over the top ends of said containers and continuously over adjacent upstanding three-container sides and the bottom of said cluster, thereby defining upper and side and bottom panels of said wrap, said upper panel providing the only cover of said top ends and having spaced slits along two parallel horizontal alignments which are substantially in registry with the upper-panel intercept of the vertical planes in which the center two containers are adjacent to their respective next-adjacent outer containers of the array, said bottom panel including overlapped edges of wrapped sheet material, said edges being bonded to each other at spaced regions which are also intercepted by said planes and at the respective ends of the region of overlap, and said slits extending substantially the full extent of said upper panel and between said side panels, said slits being so narrow that the top panel extends essentially as a continuous cover over the containers whereby the containers are substantially protected against the entry of dust through said slits.
 2. The package of claim 1, in which the plastic sheet material is of the bi-axially oriented variety, the direction of primary shrink potential being the direction of wrap.
 3. The package of claim 1, wherein said sheet material is biaxially oriented polyethylene, the direction of primary shrink potential being the direction of wrap. 